GB271400A - Improvements in or relating to variable tuning condensers - Google Patents

Abstract

271,400. Danielson, E. G. May 24, 1926, [Convention date]. Condensers have a drive connection between a control shaft and a pair of relatively movable electrodes and means for varying the minimum capacity between the electrodes without effecting an adjustment of the central shaft. Each electrode consists of a number of plates 10 rotatably mounted on spindles 11 on an insulating base 12, and the two are oppositely rotated by means. of meshing gears 18 from a control shaft 19. The drive connection comprises a cam 27 on the latter provided with a cam groove 28 of a contour such as to give the necessary movement to the electrodes, the groove engaging a pin 29 on a lever 23 which is pivoted at 24 to the base 12 and has a connection 26 with one of the gears 18 so that the latter are rotated by rocking movement cf the lever. The connection 26 is such as to enable the minimum capacity position of the condenser to be varied without affecting either the law, or the maximum capacity of the condenser, or the range of movement of the control shaft 19. Thus, both the lever 23 and gear 18 have slots 31, 32 to receive the pin 33 which is adjustable (Fig. 6) by means of a screw 40 along the slots against the action of a spring 41, the screw 40 being mounted in a plate 37 on the gear. The slots are so arranged as to be aligned in the maximum position, so that movement of the screw 40 has no effect on the electrodes. However, in the minimum position, they are at an angle to one another so that movement of the screw causes, rotation of the gear 18 and hence a change in the minimum capacity, the lever, cam, and control shaft remaining fixed. A friction device in the form of a spring 44 prevents undesired movement of the electrodes by pressing on the cam by means of a screw 45, and a connection to the spring may be used for earthing the cam, shaft, and lever.